Picture frame



FIG. 1 is a perspective view of a picture frame showing my new design;

FIG. 2 is a front plan view thereof;

FIG. 3 is a top view thereof, the bottom view being a mirror image;

FIG. 4 is a right side view thereof, the left side view being a mirror image; and,

FIG. 5 is a front view of a second embodiment of my design.

The dashed lines in FIGS. 1, 3 and 4 are shown for environmental purposes only and form no part of the claimed design. 

The ornamental design for a picture frame, as shown and described. 